Editing Transverse wave (section)

{{short description|Moving wave that has oscillations perpendicular to the direction of the wave}}
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[[File:Onde cisaillement impulsion 1d 30 petit.gif|thumb|305px|Illustration of a simple (plane) transverse wave propagating through an elastic medium in the horizontal direction, with particles being displaced in the vertical direction.  Only one layer of the material is shown]]
[[File:Electromagneticwave3D.gif|thumb|305px|Illustration of the electric (red) and magnetic (blue) fields along a ray in a simple light wave.  For any plane perpendicular to the ray, each field has always the same value at all points of the plane.]]
[[Image:Ondes cisaillement 2d 20 petit.gif|thumb|305px|Propagation of a transverse spherical wave in a 2d grid (empirical model)]]

In [[physics]], a '''transverse wave''' is a [[wave]] that oscillates perpendicularly to the direction of the wave's advance. In contrast, a [[longitudinal wave]] travels in the direction of its oscillations. All waves move energy from place to place without transporting the matter in the [[transmission medium]] if there is one.<ref>{{Cite web |title=Transverse Waves |url=https://www.physics.wisc.edu/ingersollmuseum/exhibits/waves/transverse/ |access-date=2024-03-06 |website=L.R. Ingersoll Physics Museum |language=en-US}}</ref><ref>{{Cite web |date=2020-03-05 |title=Explainer: Understanding waves and wavelengths |url=https://www.snexplores.org/article/explainer-understanding-waves-and-wavelengths |access-date=2024-03-06 |language=en-US}}</ref> [[Electromagnetic waves]] are transverse without requiring a medium.<ref>{{Cite web |title=Transverse Waves |url=https://www.memphis.edu/physics/demonstrations/transverse_waves.php |access-date=2024-03-06 |website=www.memphis.edu |language=en}}</ref> The designation “transverse” indicates the direction of the wave is perpendicular to the displacement of the particles of the medium through which it passes, or in the case of EM waves, the oscillation is perpendicular to the direction of the wave.<ref>{{Cite web |title=Physics Tutorial: The Anatomy of a Wave |url=https://www.physicsclassroom.com/class/waves/Lesson-2/The-Anatomy-of-a-Wave |access-date=2024-03-06 |website=www.physicsclassroom.com}}</ref>

A simple example is given by the waves that can be created on a horizontal length of string by anchoring one end and moving the other end up and down. Another example is the waves that are created on the membrane of a [[drum]]. The waves propagate in directions that are parallel to the membrane plane, but each point in the membrane itself gets displaced up and down, perpendicular to that plane. [[Light]] is another example of a transverse wave, where the oscillations are the [[electric field|electric]] and [[magnetic field]]s, which point at right angles to the ideal light rays that describe the direction of propagation.

Transverse waves commonly occur in [[elasticity (physics)|elastic]] solids due to the [[shear stress]] generated; the oscillations in this case are the displacement of the solid particles away from their relaxed position, in directions perpendicular to the propagation of the wave.  These displacements correspond to a local [[shear deformation]] of the material. Hence a transverse wave of this nature is called a '''shear wave'''. Since fluids cannot resist shear forces while at rest, propagation of transverse waves inside the bulk of fluids is not possible.<ref>{{Cite web|title=Fluid Mechanics II: Viscosity and Shear stresses|url=http://www.homepages.ucl.ac.uk/~uceseug/Fluids2/Notes_Viscosity.pdf#page=1|access-date=|website=}}</ref> In [[seismology]], shear waves are also called '''secondary waves''' or '''S-waves'''.

Transverse waves are contrasted with [[longitudinal waves]], where the oscillations occur in the direction of the wave.  The standard example of a longitudinal wave is a [[sound wave]] or "pressure wave" in gases, liquids, or solids, whose oscillations cause compression and expansion of the material through which the wave is propagating.  Pressure waves are called "primary waves", or "P-waves" in geophysics.

[[Gravity wave|Water wave]]s involve both longitudinal and transverse motions.<ref>{{Cite web|title=Longitudinal and Transverse Wave Motion|url=https://www.acs.psu.edu/drussell/demos/waves/wavemotion.html}}</ref>